Vitreous surgery was first performed in 1971, and involves the removal of the vitreous gel from the posterior aspect of the eye for treatment of a variety of disease states, including vitreous hemorrhage, macular disorders, retinal detachment, and many others. One common procedure involves the use of 3 incisions peripheral to the cornea to access the vitreous cavity. One port is used for infusion, one for illumination, and the third for suction/cutting instruments, as well as picks, scissors, forceps and others.
As the surgical approaches have evolved, smaller incisions are being used. The most common incision size currently is 20 gauge (1.0 mm diameter), but newer instruments as small as 25 gauge (0.49 mm diameter) are being introduced, and smaller instruments are likely in the future. The advantages of smaller incisions are multiple, including lessened trauma, faster healing, faster wound management (no sutures), and greater patient comfort.
Problems exist with the smaller instruments, however. The small diameter of the instruments makes them quite flexible, which is a disadvantage for the surgeon. With larger diameter instruments, there is very little “play”, so the tips of the instruments go exactly where the surgeon desires that they go. With the smaller diameter instruments, the tips can move from their intended positions due to the bending or flexing of the fine wire-like instruments, which makes the surgeon feel a loss of control.
Bending or flexing of the small instruments is of particular concern during removal of peripheral vitreous, when the eye must be turned to allow viewing by the surgeon. Turning of the eye is accomplished by moving the instrument relative to the patient's head while a portion of the instrument remains inserted within a portion of the eye. Because the amount of flexing of the instrument is relatively large and unpredictable to the surgeon, precise repositioning of the eye becomes more difficult.
What is needed is an instrument design that accommodates increasingly small diameters, and still provides precise control without unwanted flexing.